The present invention relates to a card-type electronic device adapted to be set in an information apparatus, such as a portable computer, and capable of receiving and providing information.
In order to add functions to or increase the data throughput of an information apparatus such as a portable computer, a card-type electronic device (PC card) is attached to a slot of the apparatus. This card-type electronic device is loaded with a cartridge that is composed of a disk-type storage medium rotatably stored in a shell.
A prior art example of the card-type electronic device described above will now be described with reference to FIGS. 14, 15A and 15B.
A card-type electronic device 1 comprises a casing 4 that has external dimensions based on Type II of the PCMCIA (Personal Computer Memory Card International Association) standards. The casing 4 is formed by combining metallic upper and lower covers 6 and 7 and a frame 5 of a synthetic resin (see FIGS. 15A and 15B).
The casing 4 has a storage space for a cartridge 17 therein, and is stored with mechanical parts (not shown), such as a motor for driving a magnetic recording disk 52 and a motor for driving a recording/reproducing head, a circuit board (not shown) for controlling these motors, and the like.
The front end portion of the casing 4 is fitted with a connector 2 that can engage a connector attached to a computer (not shown). On the other hand, the rear end portion of the casing 4 is formed with a cartridge inlet slot 90 through which the cartridge 17 is inserted into the card-type electronic device 1 (i.e., into the cartridge storage space of the casing 4).
The cartridge 17 is composed of a disk casing 95 and a magnetic recording disk 52 for use as a magnetic storage medium that is stored in the disk casing 95 and rotatably supported by means of the disk casing 95.
As the card-type electronic device 1 is moved in the direction of arrow A of FIG. 14, it is inserted into a slot in the computer, and the connector 2 engages a pin on the computer. As the cartridge 17 is moved in the direction of arrow B of FIG. 14, moreover, it is loaded into the card-type electronic device 1 through the cartridge inlet slot 90.
Since the card-type electronic device 1 is based on Type II of the PCMCIA standards, as mentioned before, its external dimensions (width by length by thickness) are 54.0 mm by 85.60 mm by 5.0 mm.
According to the PCMCIA standards, moreover, it is stipulated that the respective front end portions (connector storage portions 6b and 7b mentioned later) and left- and right-hand sides (insertion guide portions 6d and 7d mentioned later; the insertion guide portion 7d of the lower cover 7 is not shown in FIG. 14) of the upper and lower covers 6 and 7 that constitute the casing 4 should be formed with step portions that are 0.8 mm to 0.9 mm lower than central portions (internal component storage portions 6a and 7a mentioned later).
Further, the thickness (T1 of FIG. 15A) of a collar portion 2a (mentioned later) of the connector 2 and the distance (equal to T1 of FIG. 15B, that is, the distance between a connector storage portion 6b flush with the insertion guide portion 6d and the connector storage portion 7b flush with the insertion guide portion 7d) between the insertion guide portion 6d of the upper cover 6 and the insertion guide portion 7d of the lower cover 7 that serve as guides for the insertion into the slot of the computer are both 3.3 mm (standard).
In the PC card of this type, as is described in Registered Japanese Utility Model No. 3024721 and Japanese Patent Application Laid-open 5-254286, stepped peripheral edge portions are formed individually on the respective peripheral portions of upper and lower covers by step drawing in order to form the aforesaid step portions, the respective inner surfaces of the peripheral edge portions are fixed individually to the upper and lower surfaces of a frame 5 by adhesive bonding, laser welding, or brazing, and the upper and lower covers and the frame 5 are assembled to form a casing, in general.
Since the cartridge 17 shown in FIG. 14 has the magnetic recording disk 52 stored for rotation therein, moreover, it is expected to have a fixed thickness. In consequence, a satisfactory thickness must be given to the casing 4 in order to store the cartridge 17 with the fixed thickness in the casing 4 that is composed of the upper and lower covers 6 and 7.
The satisfactory thickness can be given to the casing 4 by narrowing the areas of the lower-step portions (i.e., connector storage portions 6b and 7b and insertion guide portions 6d and 7d) that are formed on the respective front end portions and left- and right-hand side portions of the upper and lower covers 6 and 7, thereby widening the areas of the elevated central portions (internal component storage portions 6a and 7a) correspondingly.
However, the lower-step portions at the respective front end portions and left- and right-hand side portions of the upper and lower covers 6 and 7 are utilized as areas for adhesive bonding with the frame 5. If these areas are narrowed, therefore, the areas of adhesive bonding between the metallic covers (upper and lower covers 6 and 7) and the synthetic resin frame 5 are reduced, so that bonding force between the metallic covers 6 and 7 and the synthetic resin frame is lowered inevitably. In consequence, the metallic covers 6 and 7 may is possibly separate from the frame 5 during use of the PC card.
In the PC card of the type that is loaded with the cartridge 17 storing the disk-type magnetic storage medium 52 therein, the mechanism is so complicated that the casing 4 must be opened for inspection, in some cases. If the metallic covers 6 and 7 and the synthetic resin frame 5 are fixed together by welding or brazing or bonded firmly, the metallic covers 6 and 7 cannot be removed, thus causing inconvenience.
If the metallic covers 6 and 7 are forced to be removed from the synthetic resin frame 5, moreover, a great external force acts on the casing 4, possibly destroying internal components.
Referring now to FIGS. 15A and 15B, there will be described an arrangement for bonding the connector 2 between the upper and lower covers 6 and 7 of FIG. 14.
As mentioned before, the upper and lower covers 6 and 7 are obtained by pressing thin SUS sheets with a thickness t1 of about 0.20 mm so that first flat portions (i.e., internal component storage portions 6a and 7a) are formed in their respective central portions, and second flat portions (i.e., connector storage portions 6b and 7b and insertion guide portions 6d and 7d), which are depressed toward the inner surface side from the first flat portions, are formed extending from the front portions to the opposite side portions.
The internal components, including a recording/reproducing head element, disk drive motor, etc., are stored between the respective first flat portions of the upper and lower covers 6 and 7. Thus, the respective first flat portions of the upper and lower covers 6 and 7 constitute the internal component storage portions 6a and 7a, respectively.
As shown in FIG. 14, the respective second flat portions of the upper and lower covers 6 and 7 are composed, respectively, of the insertion guide portions 6d and 7d, which serve as insertion guides for the computer, and the connector storage portions 6b and 7b for storing the connector 2. The insertion guide portions 6d and 7d and the connector storage portions 6b and 7b have no differences in level, and are formed flush with one another in pressing processes for forming the first and second storage portions individually on the upper and lower covers 6 and 7.
On the other hand, that portion (collar portion 2a) of the connector 2 which is exposed outward from the connector storage portions 6b and 7b of the second flat portions formed on the upper and lower covers 6 and 7 has the thickness (T1) of 3.3 mm (standard), and a portion (stepped junction 2b) stored between the connector storage portions 6b and 7b has a thickness (T2) of about 2.8 mm. As shown in FIG. 15A, therefore, a difference in level T3 between T1 and T2 is 0.25 mm.
As shown in FIG. 15B, moreover, a sheet thickness T4 of the frame 5 is 2.8 mm, which is equal to the thickness T2(=2.8 mm) of the stepped junction 2b formed on the connector 2.
The fixing between the connector storage portions 6b and 7b of the second flat portions formed individually on the upper and lower covers 6 and 7, the stepped junction 2b of the connector 2, and the frame 5 is generally based on the application of an adhesive agent 38 by the screen printing method. A thickness t2 (margin for adhesive bonding) of the adhesive layer ranges from about 0.05 mm to 0.06 mm, and high workability for adhesive bonding and. required bonding strength can be secured with use of the margin for adhesive bonding corresponding to this thickness.
A dimension (=t1+t2) obtained by adding the margin (t2) for adhesive bonding to the thickness (t1) of the upper and lower covers 6 and 7 is 0.25 mm, which is equal to the dimension (0.25 mm) of the aforesaid difference in level T3 of the connector 2. Thus, the surface of the collar portion 2a of the connector 2 is flush with the respective surfaces of the connector storage portions 6b and 7b which are the second flat portions formed on the upper and lower covers 6 and 7, and the connector 2 is fixed to the upper and lower covers 6 and 7.
In order to improve the functions of the card-type electronic device further, it is essential to extend the storage space for the internal components. Presumably, therefore, the storage space may be extended by reducing the respective thicknesses t1 of the upper and lower covers 6 and 7 from 0.20 mm to 0.15 mm.
Thereupon, the margin t2 for adhesive bonding must be restricted within the range from 0.05 mm or 0.06 mm to 0.1 mm in order to bond the upper and lower covers 6 and 7 to the connector 2 without failing to ensure the extension of the storage space for the internal components (e.g., electronic devices mounted on the circuit board). There is a problem, however, such that the bonding strength cannot be secured in the aforesaid manner with use of a margin for adhesive bonding corresponding to a thickness of 0.1 mm.
Further, set dimensions for the thickness T2(=2.8 mm) of the stepped junction 2b of the connector 2 vary according to manufacturers. In the case where T2=2.7 mm or 2.9 mm is given, for example, the margin for adhesive bonding is so unstable that the bonding strength lowers if the thickness of the collar portion of the connector is maintained T1=3.3 mm (standard), as mentioned before.
In order to solve these problems, therefore, the card-type electronic device is expected to be designed so that the respective sheet thicknesses of the upper and lower covers are reduced to enlarge the storage space for the internal components, its functions can be improved, it can cope with change of the set dimensions of the connector, and it enjoys good working accuracy and outstanding workability.
The object of the present invention is to provide a card-type electronic device comprising a casing composed of a frame for use as a storage portion for individual components and upper and lower covers covering the upper and lower surfaces, individually, of the frame, in which the upper and lower covers are coupled firmly to each other, and the upper or lower cover can be easily removed as required.
Substantially U-shaped retaining pieces are formed on the long side edge portions of at least one cover. The retaining pieces are formed substantially U-shaped by bending the respective distal ends of tongues, which partially protrude from the long side edge portions of the cover, toward the other cover and further bending the distal ends on the inner peripheral side. On the other hand, the side faces of the frame are formed with recesses for vertically guiding the retaining pieces and retaining portions adapted individually to engage the retaining pieces fitted in the recesses when the retaining pieces are slid in the longitudinal direction of the casing.
When the retaining pieces and the retaining portions engage one another, the cover and the frame are temporarily fixed to each other, whereby the cover can be prevented from coming off up- or downward.
In removing the cover, the cover is slid in the direction opposite to the direction of its attachment along the length of the casing, whereupon the retaining pieces and the retaining portions are disengaged from one another. After the retaining pieces are returned to the positions of the recesses, the retaining pieces are drawn out of the recesses.
The card-type electronic device of the present invention can further have the following configuration.
The connection between the cover and the frame is further strengthened by providing slide preventing means for preventing the retaining pieces from moving in the longitudinal direction after the cover and the frame are temporarily fixed to each other with the engagement of the retaining pieces with the retaining portions. The slide preventing means includes screwing, adhesive bonding, caulking, etc. In the case where the cover requires attachment and detachment, however, the slide preventing means is configured by screwing or weak adhesive bonding so that the cover can be easily removed from the frame.
The slide preventing means is provided on the short side of the casing. This is done because the short side of the casing affords a wider region for screwing or adhesive bonding than the long side does, so that reliable slide preventing means can be provided with ease.
A peripheral edge portion is formed on the long side edge portion of the cover by step drawing, and the tongues are provided on the distal end edge of the edge portion.
The distal end side of the edge portion that is formed by the step drawing of the cover is bent throughout its length toward the other cover, whereby a bent wall is formed. The aforesaid tongues are provided protruding from the distal end edge of the bent wall, and the tongues are bent inward along the distal end line of the bent wall, whereupon the retaining pieces are formed.
The vertical dimension of the bent wall of the cover on the top side is made different from the vertical dimension of the cover on the bottom side.
A frame plate for mounting the components on the frame is formed as one body by outsert molding or the like, and a drive unit for magnetic recording and reading is incorporated in the frame plate.
The frame is formed of a synthetic resin and is fitted integrally with the frame plate by outsert molding.
The upper cover and the frame can be temporarily fixed to each other by sliding, a magnetic recording device is mounted on the top side of the frame plate, and a circuit board is located on the bottom side. Since the magnetic recording device has a complicated delicate construction, it sometimes requires inspection. The inspection is easy if the upper cover is removable.
A connector for connecting an external information apparatus to the circuit board is provided, and this connector is exposed on one short side of the casing. Further, an inlet for a magnetic storage medium is formed on the other short side of the casing. Both these elements, like those of conventional PC cards, are easy to handle.
The slide preventing means is provided on one short side of the upper cover or lower cover.
The slide preventing means of the cover is used as fixing means that is expected to be removed or fixing means that is not expected to be removed. The slide preventing means of one of the covers, e.g., the upper cover, may be designed to be fixing means that is expected to be removed so that the cover can be easily removed to facilitate operation for inspection. Further, the strength of the casing can be kept high enough by securely fixing the lower cover to the frame.